Adhesion method, and biochemical chip and optical component made by the same

ABSTRACT

An adhesion method capable of strongly adhering two members without using an adhesive and without impairing a fine structure or optical properties of a joining surface, and a biochemical chip and optical component made by the same are provided. 
     The adhesion method includes step A of forming a coating film  13  of a first film compound having a first functional group on a first joining surface  11  of a first member  21 , step B of forming a coating film  14  of a second film compound having a second functional group on a second joining surface  12  of a second member  22 , and step C of bringing the first joining surface  11  into contact by pressure with the second joining surface  12  while bringing a coupling agent having at least one coupling reactive group that forms a bond by a coupling reaction with the first functional group and the second functional group into contact with the first and second functional groups to form bonds by the coupling reaction.

TECHNICAL FIELD

The present invention relates to an adhesion method and a biochemicalchip and optical component made by the same. More specifically, thepresent invention relates to a method of achieving adhesion withoutusing an adhesive by introducing a reactive functional group into asurface of each of joining surfaces by forming a coating film made of afilm compound having the reactive functional group, and chemicallybonding the joining surfaces via bonds formed between a coupling agentand the functional group, and a biochemical chip and optical componentmade by the same.

BACKGROUND ART

A technique in which two members are adhered to each other by applyingan adhesive to one of or both of joining surfaces, pressure-bonding thejoining surfaces to each other, and curing the adhesive is generallywell known (see, for example, Patent Document 1). However, when a finestructure (for example, a hole or groove having a size of micrometerslevel) is provided on at least one of the joining surfaces, for example,as in the case of a member of a biochemical chip, it is very difficultto achieve adhesion with no clearance without filling the fine structurewith a fluid adhesive.

In addition, by a known method using an adhesive, it is also verydifficult to achieve adhesion of an optical member such as a lenswithout degrading optical properties thereof because the thickness ofthe adhesive or the like on a joining surface becomes uneven.

As an adhesion method without using an adhesive, for example, PatentDocument 2 discloses a method of adhering foil-like or film-likematerials to each other with an organic monomolecular film therebetween.In the method described in this document, for example, aluminum foils inwhich an organic monomolecular film having an aliphatic hydrocarbongroup is bonded to a surface thereof adhere to each other throughintermolecular force and a negative pressure.

Patent Document 1: Japanese Unexamined Patent Application PublicationNo. 2005-221478 Patent Document 2: Japanese Unexamined PatentApplication Publication No. 2003-246971 DISCLOSURE OF INVENTION Problemto be Solved by the Invention

However, in the method described in Patent Document 2 in which adhesionis achieved utilizing intermolecular force acting on an organicmonomolecular film and a negative pressure during pressure bonding ofmembers, the adhesive strength is too low, and thus the method cannot beapplied to adhesion of a biochemical chip, an optical component, or thelike.

The present invention has been made in view of the above problem, and itis an object of the present invention to provide an adhesion methodcapable of strongly adhering two members without using an adhesive andwithout impairing a fine structure or optical properties of a joiningsurface, and a biochemical chip and optical component made by the same.

Means for Solving the Problems

An adhesion method according to a first invention that achieves theabove object is a method of adhering a first joining surface of a firstmember to a second joining surface of a second member including step Aof bringing a first film compound having a first functional group at anend of its molecule and a first surface bonding group at another endthereof into contact with the first joining surface to form a bondbetween the first surface bonding group and a surface functional groupof the first joining surface, thereby forming a coating film of thefirst film compound on the first joining surface; step B of bringing asecond film compound having a second functional group at an end of itsmolecule and a second surface bonding group at another end thereof intocontact with the second joining surface to form a bond between thesecond surface bonding group and a surface functional group of thesecond joining surface, thereby forming a coating film of the secondfilm compound on the second joining surface; and step C of bringing thefirst joining surface having the coating film of the first film compoundthereon into contact by pressure with the second joining surface havingthe coating film of the second film compound thereon while setting acoupling agent having at least one first coupling functional group thatforms a bond by a coupling reaction with the first functional group andat least one second coupling reactive group that forms a bond by acoupling reaction with the second functional group to be in contact withthe first functional group and the second functional group to form bondsby coupling reactions between the first functional group and the firstcoupling reactive group and between the second functional group and thesecond coupling reactive group.

In the adhesion method according to the first invention, in step C,first, the coupling agent may be brought into contact with the coatingfilm of the first film compound formed on the first joining surface toform a bond by a coupling reaction between the first functional groupand the first coupling reactive group, thereby forming a coating film ofthe coupling agent on the surface of the coating film of the first filmcompound, and the first joining surface further having the coating filmof the coupling agent thereon may then be brought into contact bypressure with to the second joining surface having the coating film ofthe second film compound thereon to form a bond by a coupling reactionbetween the second functional group and the second coupling reactivegroup.

In the adhesion method according to the first invention, each of thefirst functional group and the second functional group may be afunctional group containing an epoxy group, and the coupling agent maybe a compound containing an imidazole group.

In the adhesion method according to the first invention, each of thefirst surface bonding group and the second surface bonding group may bean alkoxysilyl group.

In the adhesion method according to the first invention, in step C, thefirst member and the second member are preferably heated at the sametemperature.

A biochemical chip according to a second invention includes a firstmember and a second member, wherein, on a first joining surface of thefirst member, a coating film of a first film compound having a firstfunctional group at an end of its molecule and bonded to the firstjoining surface at another end thereof is provided, on a second joiningsurface of the second member, a coating film of a second film compoundhaving a second functional group at an end of its molecule and bonded tothe second joining surface at another end thereof is provided, the firstfunctional group and the second functional group are bonded to eachother via bonds formed by coupling reactions between the firstfunctional group and a coupling agent having at least one first couplingreactive group that forms a bond by a coupling reaction with the firstfunctional group and at least one second coupling reactive group thatforms a bond by a coupling reaction with the second functional group andbetween the second functional group and the coupling agent, and thefirst joining surface is adhered to the second joining surface via theformed bonds.

In the present invention, the term “biochemical chip” refers to achemical device for performing an operation such as mixing, synthesis,extraction, purification, analysis, or measurement of a compound in achannel having a width on the order of micrometers. Specific examplesthereof include a chemical chip, a biochip, a biochemicalelectrophoresis chip, a biochemical reactor, a biochemical fluid system,and a DNA chip, which are used in a chemical experiment, abio-experiment, medical diagnosis, and the like.

In the biochemical chip according to the second invention, each of thefirst functional group and the second functional group may be afunctional group containing an epoxy group, and the coupling agent maybe a compound containing an imidazole group.

In the biochemical chip according to the second invention, each of thecoating film of the first film compound and the coating film of thesecond film compound is preferably a monomolecular film.

An optical component according to a third invention includes a firstmember and a second member, wherein, on a first joining surface of thefirst member, a coating film of a first film compound having a firstfunctional group at an end of its molecule and bonded to the firstjoining surface at another end thereof is provided, on a second joiningsurface of the second member, a coating film of a second film compoundhaving a second functional group at an end of its molecule and bonded tothe second joining surface at another end thereof is provided, the firstfunctional group and the second functional group are bonded to eachother via bonds formed by coupling reactions between the firstfunctional group and a coupling agent having at least one first couplingreactive group that forms a bond by a coupling reaction with the firstfunctional group and at least one second coupling reactive group thatforms a bond by a coupling reaction with the second functional group andbetween the second functional group and the coupling agent, and thefirst joining surface is adhered to the second joining surface via theformed bonds.

In the present invention, the term “optical component” refers to anylight-transmissive member used in an optical instrument. Specificexamples thereof include a lens, a prism, an optical fiber, and anoptical recording medium.

In the optical component according to the third invention, each of thefirst functional group and the second functional group may be afunctional group containing an epoxy group, and the coupling agent maybe a compound containing an imidazole group.

In the optical component according to the third invention, each of thecoating film of the first film compound and the coating film of thesecond film compound is preferably a monomolecular film.

EFFECT OF THE INVENTION

In the adhesion methods described in Claims 1 to 5, a first filmcompound and a second film compound covering a first joining surface anda second joining surface, respectively, are strongly bonded to the firstjoining surface and the second joining surface, respectively, viacovalent bonds, and a first functional group and a second functionalgroup are strongly bonded to each other via covalent bonds formed bycoupling reactions with a coupling agent. Accordingly, the first joiningsurface can be strongly bonded to the second joining surface.

In addition, no adhesive is used, and thus adhesion can be achievedwithout impairing a fine structure formed on a joining surface oroptical properties. Therefore, the methods can be suitably used inadhesion of a biochemical chip or an optical component.

In particular, in the adhesion method described in Claim 2, first, thecoupling agent is brought into contact with the coating film of thefirst film compound formed on the first joining surface to form a bondby a coupling reaction between the first functional group and a firstcoupling reactive group, thereby forming a coating film of the couplingagent on the surface of the coating film of the first film compound, andthe first joining surface further having the coating film of thecoupling agent thereon is then brought into contact by pressure with thesecond joining surface having the coating film of the second filmcompound thereon to form a bond by a coupling reaction between thesecond functional group and a second coupling reactive group.Accordingly, excess coupling agent can be removed before adhesion.Therefore, elution of excess coupling agent after adhesion anddegradation of optical properties due to discoloration can besuppressed.

In the adhesion method described in Claim 3, each of the firstfunctional group and the second functional group is a functional groupcontaining an epoxy group, and the coupling agent is a compoundcontaining an imidazole group. Accordingly, strong bonds can be formedby heating at a relatively low temperature.

In the adhesion method described in Claim 4, each of the first surfacebonding group and the second surface bonding group is an alkoxysilylgroup. Accordingly, they can form a strong bond on a joining surfacehaving an active hydrogen group such as a hydroxyl group via a covalentbond (siloxane bond).

In the adhesion method described in Claim 5, in step C, by heating thefirst member and the second member at the same temperature, generationof thermal distortion can be suppressed, and thus the dimensionalaccuracy of the first joining surface and the second joining surface inthe adhesion can be improved.

In the biochemical chips described in Claims 6 to 8, a first filmcompound and a second film compound covering a first joining surface anda second joining surface, respectively, are strongly bonded to the firstjoining surface and the second joining surface, respectively, viacovalent bonds, and a first functional group and a second functionalgroup are strongly bonded to each other via covalent bonds formed bycoupling reactions with a coupling agent.

Accordingly, the first joining surface can be strongly bonded to thesecond joining surface. In addition, adhesion is achieved without usingan adhesive, and thus the biochemical chips can be made without clogginga groove-like or hole-like fluid channel provided on a joining surfaceand having a size of micrometers level.

In the biochemical chip described in Claim 7, each of the firstfunctional group and the second functional group is a functional groupcontaining an epoxy group, and the coupling agent is a compoundcontaining an imidazole group. Accordingly, strong bonds can be formedby heating at a relatively low temperature.

In the biochemical chip described in Claim 8, each of the coating filmof the first film compound and the coating film of the second filmcompound is a monomolecular film. Accordingly, the dimensional accuracyin the adhesion can be improved.

In the optical components described in Claims 9 to 11, a first filmcompound and a second film compound covering a first joining surface anda second joining surface, respectively, are strongly bonded to the firstjoining surface and the second joining surface, respectively, viacovalent bonds, and a first functional group and a second functionalgroup are strongly bonded to each other via covalent bonds formed bycoupling reactions with a coupling agent. Accordingly, the first joiningsurface can be strongly bonded to the second joining surface. Inaddition, adhesion is achieved without using an adhesive, and thus theoptical components can be made without impairing optical properties ofthe joining surfaces.

In the optical component described in Claim 10, each of the firstfunctional group and the second functional group is a functional groupcontaining an epoxy group, and the coupling agent is a compoundcontaining an imidazole group. Accordingly, strong bonds can be formedby heating at a relatively low temperature.

In the optical component described in Claim 11, each of the coating filmof the first film compound and the coating film of the second filmcompound is a monomolecular film. Accordingly, the dimensional accuracyin the adhesion can be improved.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is an explanatory view that schematically shows a partialstructure of a cross section of a biochemical chip according to anembodiment of the present invention.

FIG. 2 is a conceptual view in which the vicinity of a surface of afirst base material before and after formation of a coating film of afirst film compound is enlarged to the molecular level in order toillustrate a step of forming the coating film of the first film compoundon a first joining surface in a method of producing the biochemicalchip.

FIG. 3 is a conceptual view in which the vicinity of the surface of thefirst base material before and after formation of a coating film of acoupling agent is enlarged to the molecular level in order to illustratea step of forming the coating film of the coupling agent on the surfaceof the first film compound in the method of producing the biochemicalchip.

BEST MODES FOR CARRYING OUT THE INVENTION

Embodiments of the present invention will now be described withreference to the drawings to achieve the understanding of the presentinvention. FIG. 1 is an explanatory view that schematically shows apartial structure of a cross section of a biochemical chip according toan embodiment of the present invention. FIG. 2 is a conceptual view inwhich the vicinity of a surface of a first base material before andafter formation of a coating film of a first film compound is enlargedto the molecular level in order to illustrate a step of forming thecoating film of the first film compound on a first joining surface in amethod of producing the biochemical chip. FIG. 3 is a conceptual view inwhich the vicinity of the surface of the first base material before andafter formation of a coating film of a coupling agent is enlarged to themolecular level in order to illustrate a step of forming the coatingfilm of the coupling agent on the surface of the first film compound inthe method of producing the biochemical chip.

As shown in FIGS. 1 to 3, a biochemical chip 10 according to anembodiment of the present invention includes a first base material (anexample of a first member) 21 and a second base material 22 (an exampleof a second member) 22. On a first joining surface 11 of the first basematerial 21, a monomolecular film 13 which is an example of a coatingfilm of a first film compound that has an epoxy group (an example of afirst functional group) at one end of its molecule and that is bonded tothe first joining surface 11 at another end thereof is provided. On asecond joining surface 12 of the second base material 22, amonomolecular film 14 which is an example of a coating film of a secondfilm compound that has an epoxy group (an example of a second functionalgroup) at one end of its molecule and that is bonded to the secondjoining surface 12 at another end thereof is provided. The epoxy groupon the monomolecular film 13 of the first film compound and the epoxygroup on the monomolecular film 14 of the second film compound arebonded to each other via bonds formed by coupling reactions between eachof the epoxy groups and 2-methylimidazole (an example of a couplingagent) having, in its molecule, an amino group and an imino group (anexample of a first coupling reactive group and an example of a secondcoupling reactive group) each of which undergoes a coupling reactionwith an epoxy group to form a bond. The first joining surface 11 and thesecond joining surface 12 adhere to each other via the bonds formed asdescribed above.

The biochemical chip 10 is produced by an adhesion method including stepA (see FIG. 2) of bringing a first film compound having an epoxy groupat an end of its molecule and an alkoxysilyl group (an example of afirst surface bonding group) at another end thereof into contact with afirst joining surface 11 of a first base material 21 to form amonomolecular film 13 of the first film compound via a bond formedbetween the alkoxysilyl group and a hydroxyl group (an example of asurface functional group of the first joining surface 11) 23; step B offorming a monomolecular film 14 of a second film compound on a secondjoining surface 12 of a second base material 22 via a bond formedbetween an alkoxysilyl group and a hydroxyl group (an example of asurface functional group of the second joining surface 12) by the samemethod as that in step A; and step C of, first, bringing2-methylimidazole into contact with the monomolecular film 13 of thefirst film compound to form a bond by a coupling reaction between theepoxy group and an amino group of 2-methylimidazole, thereby forming amonomolecular film 15 of a 2-methylimidazole derivative (an example ofcoating film of a coupling agent) on the surface of the monomolecularfilm 13 of the first film compound; and then bringing the first joiningsurface 11 further having the monomolecular film 15 of the2-methylimidazole derivative thereon into contact by pressure with thesecond joining surface 12 having the monomolecular film 14 of the secondfilm compound thereon to form a bond by a coupling reaction between anepoxy group and an imino group of 2-methylimidazole.

Steps A to C will now be described in more detail.

In step A, a first film compound having an epoxy group is brought intocontact with a first joining surface 11 of a first base material 21 madeof glass to form a monomolecular film 13 of the first film compoundhaving an epoxy group on the first joining surface 11 (see FIG. 2). Thesize and the shape of the first base material 21 that can be used arenot particularly limited, but the first joining surface 11 preferablyhas a mirror-finished surface having a surface roughness of 1 μm orless, and preferably 100 nm or less.

As the first film compound having an epoxy group, any compound that canbe adsorbed or bonded to a surface of the first base material 21 to forma monomolecular film by self-assembly can be used. An alkoxysilanecompound in which a functional group containing an epoxy group (oxiranering) is disposed at an end of a straight-chain alkylene group and analkoxysilyl group is disposed at another end thereof, and which isrepresented by a general formula (Chem. 1) below is preferable.

E-(CH₂)_(m)—Si(OR)₃  [Chem. 1]

In the above formula, E represents a functional group having an epoxygroup, m represents an integer in the range of 3 to 20, and R representsan alkyl group having 1 to 4 carbon atoms.

Specific examples of the first film compound having an epoxy group thatcan be used include alkoxysilane compounds represented by (1) to (12)below.

In the case where the surface roughness of the joining surface is large,a film compound having a long molecular chain is preferably used.

(CH₂OCH)CH₂O(CH₂)₃Si(OCH₃)₃  (1)

(CH₂OCH)CH₂O(CH₂)₇Si(OCH₃)₃  (2)

(CH₂OCH)CH₂O(CH₂)₁₁Si(OCH₃)₃  (3)

(CH₂CHOCH(CH₂)₂)CH(CH₂)₂Si(OCH₃)₃  (4)

(CH₂CHOCH(CH₂)₂)CH(CH₂)₄Si(OCH₃)₃  (5)

(CH₂CHOCH(CH₂)₂)CH(CH₂)₆Si(OCH₃)₃  (6)

(CH₂OCH)CH₂O(CH₂)₃Si(OC₂H₅)₃  (7)

(CH₂OCH)CH₂O(CH₂)₇Si(OC₂H₅)₃  (8)

(CH₂OCH)CH₂O(CH₂)₁₁Si(OC₂H₅)₃  (9)

(CH₂CHOCH(CH₂)₂)CH(CH₂)₂Si(OC₂H₅)₃  (10)

(CH₂CHOCH(CH₂)₂)CH(CH₂)₄Si(OC₂H₅)₃  (11)

(CH₂CHOCH(CH₂)₂)CH(CH₂)₆Si(OC₂H₅)₃  (12)

Here, a (CH₂OCH)CH₂O— group represents a functional group (glycidyloxygroup) represented by Chem. 2, and a (CH₂CHOCH(CH₂)₂)CH— grouprepresents a functional group (3,4-epoxycyclohexyl group) represented byChem. 3.

The monomolecular film 13 of the first film compound is formed byapplying a reaction mixture containing an alkoxysilane compound havingan epoxy group, a condensation catalyst for accelerating a condensationreaction between an alkoxysilyl group and a hydroxyl group 23 disposedon a surface of the first base material 21, and a nonaqueous organicsolvent on the surface of the first base material 21, and allowing thereaction mixture to react in air at room temperature. The applicationcan be performed using any method such as a doctor blade method, adip-coating method, a spin-coating method, a spray method, a screenprinting method, or an ink jet printing method.

As the condensation catalyst, a metal salt such as a carboxylic acidmetal salt, a carboxylate metal salt, a carboxylic acid metal saltpolymer, a carboxylic acid metal salt chelate, a titanate, or a titanatechelate can be used.

The amount of condensation catalyst added is preferably in the range of0.2 to 5 mass percent, and more preferably in the range of 0.5 to 1 masspercent of the alkoxysilane compound.

Specific examples of the carboxylic acid metal salt include stannousacetate, dibutyltin dilaurate, dibutyltin dioctoate, dibutyltindiacetate, dioctyltin dilaurate, dioctyltin dioctoate, dioctyltindiacetate, stannous dioctoate, lead naphthenate, cobalt naphthenate, andiron 2-ethylhexenoate.

Specific examples of the carboxylate metal salt include dioctyltinbisoctyl thioglycolate and dioctyltin maleate.

Specific examples of the carboxylic acid metal salt polymer includedibutyltin maleate polymers and dimethyltin mercaptopropionate polymers.

Specific examples of the carboxylic acid metal salt chelate includedibutyltin bisacetylacetate and dioctyltin bisacetyllaurate.

Specific examples of the titanate include tetrabutyl titanate andtetranonyl titanate.

A specific example of the titanate chelate isbis(acetylacetonyl)dipropyl titanate.

A condensation reaction between the alkoxysilyl group and the hydroxylgroup 23 disposed on the surface of the first base material 21 occurs toproduce the monomolecular film 23 which is made of the first filmcompound having an epoxy group and which has the structure representedby Chem. 4 below. Three single bonds extending from oxygen atoms arebonded to silicon (Si) atoms of the surface of the first base material21 or silicon atoms of an adjacent silane compound. Among the threesingle bonds, at least one single bond is bonded to a silicon atom ofthe surface of the first base material 21.

The reaction is preferably performed in air with a relative humidity of45% or less because the alkoxysilyl group is decomposed in the presenceof moisture. Note that the condensation reaction is inhibited by greaseand moisture adhered to the surface of the first base material 21.Therefore, it is preferable that these impurities are removed in advanceby sufficiently washing and then drying the first base material 21.

In the case where any one of the above-mentioned metal salts is used asthe condensation catalyst, the time required for completing thecondensation reaction is about two hours.

In the case where one or more compounds selected from the groupconsisting of ketimine compounds, organic acids, aldimine compounds,enamine compounds, oxazolidine compounds, and aminoalkylalkoxysilanecompounds are used as the condensation catalyst instead of theabove-mentioned metal salts, the reaction time can be reduced to about ½to ⅔.

Alternatively, when these compounds are used as a cocatalyst as amixture with the above-mentioned metal salts (these compounds can beused in a mass ratio in the range of 1:9 to 9:1, but the mass ratio ispreferably about 1:1), the reaction time can be further reduced.

For example, when the monomolecular film 13 of the first film compoundis formed under the same conditions except that H3 manufactured by JapanEpoxy Resins Co., Ltd., which is a ketimine compound, is used as thecondensation catalyst instead of dibutyltin bisacetylacetate, which is acarboxylic acid metal salt chelate, the reaction time can be reduced toabout one hour without impairing the quality of the first base material21.

Furthermore, when the monomolecular film 13 of the first film compoundis formed under the same conditions except that a mixture (mixing ratio:1:1) of H3 manufactured by Japan Epoxy Resins Co., Ltd. and dibutyltinbisacetylacetonate is used as the condensation catalyst, the reactiontime can be reduced to about 20 minutes.

Examples of the ketimine compound that can be used here include, but arenot particularly limited to, 2,5,8-triaza-1,8-nonadiene,3,11-dimethyl-4,7,10-triaza-3,10-tridecadiene,2,10-dimethyl-3,6,9-triaza-2,9-undecadiene,2,4,12,14-tetramethyl-5,8,11-triaza-4,11-pentadecadiene,2,4,15,17-tetramethyl-5,8,11,14-tetraaza-4,14-octadecadiene, and2,4,20,22-tetramethyl-5,12,19-triaza-4,19-trieicosadiene.

Examples of the organic acid that can be used include, but are also notparticularly limited to, formic acid, acetic acid, propionic acid,butyric acid, and malonic acid.

In producing the reaction mixture, an organochlorine solvent, ahydrocarbon solvent, a fluorocarbon solvent, a silicone solvent, and amixed solvent thereof can be used. In order to prevent hydrolysis of thealkoxysilane compound, it is preferable that moisture is removed inadvance from the solvent used using a desiccant or by distillation. Theboiling point of the solvent is preferably in the range of 50° C. to250° C.

Specific examples of the solvent that can be used include nonaqueouspetroleum naphtha, solvent naphtha, petroleum ether, petroleum benzine,isoparaffin, normal paraffin, decalin, industrial gasoline, nonane,decane, heating oil, dimethyl silicone, phenyl silicone, alkyl-modifiedsilicone, polyether silicone, and dimethylformamide.

Furthermore, an alcohol solvent such as methanol, ethanol, or propanol,or a mixture thereof can also be used.

Examples of the fluorocarbon solvent that can be used include flonsolvents, Fluorinert (manufactured by 3M in the United States), andAflude (manufactured by Asahi Glass Co., Ltd.). These may be used aloneor in combinations of two or more solvents that can be sufficientlymixed with each other. Furthermore, an organochlorine solvent such asdichloromethane or chloroform may be added.

A preferable concentration of the alkoxysilane compound in the reactionmixture is in the range of 0.5 to 3 mass percent.

After the reaction, washing is performed with a solvent to remove excessalkoxysilane compound and condensation catalyst remaining on the surfaceas unreacted products. Consequently, the monomolecular film 13 of thefirst film compound is formed on the first joining surface 11. Aschematic view of the vicinity of the first joining surface 11 on whichthe monomolecular film 13 of the first film compound is thus formed isshown in FIG. 2.

Any solvents that can dissolve the alkoxysilane compound can be used asthe washing solvent. For example, dichloromethane, chloroform, orN-methylpyrrolidone, which is inexpensive, which can solve thealkoxysilane, and which can be easily removed by air drying ispreferable.

After the reaction, when the first base material 21 is left to stand inair without washing with a solvent, a portion of the alkoxysilanecompound remaining on the surface is hydrolyzed by moisture in air, anda condensation reaction between a resulting silanol group and analkoxysilyl group occurs. As a result, an ultrathin polymer film made ofpolysiloxane is formed on the first joining surface 11. This polymerfilm is not necessarily completely fixed on the first joining surface 11by covalent bonding. However, the polymer film contains an epoxy group,and thus has a reactivity similar to that of the monomolecular film 13of the first film compound. Therefore, even if washing is not performed,no particular problem occurs in the subsequent production process.

In this embodiment, an alkoxysilane compound having an epoxy group isused. Alternatively, an alkoxysilane compound in which an amino group isdisposed at an end of a straight-chain alkylene group and an alkoxysilylgroup is disposed at another end thereof, and which is represented by ageneral formula (Chem. 5) below may be used.

H₂N—(CH₂)_(m)—Si(OR)₃  [Chem. 5]

In the above formula, m represents an integer in the range of 3 to 20,and R represents an alkyl group having 1 to 4 carbon atoms.

Specific examples of the film compound having an amino group that can beused include alkoxysilane compounds represented by (21) to (28) below.

H₂N(CH₂)₃Si(OCH₃)₃  (21)

H₂N(CH₂)₅Si(OCH₃)₃  (22)

H₂N(CH₂)₇Si(OCH₃)₃  (23)

H₂N(CH₂)₉Si(OCH₃)₃  (24)

H₂N(CH₂)₅Si(OC₂H₅)₃  (25)

H₂N(CH₂)₅Si(OC₂H₅)₃  (26)

H₂N(CH₂)₇Si(OC₂H₅)₃  (27)

H₂N(CH₂)₉Si(OC₂H₅)₃  (28)

Among the condensation catalysts that can be used in the reactionmixture, compounds containing a tin (Sn) salt cannot be used as acondensation catalyst for an alkoxysilane compound having an amino groupbecause such compounds react with the amino group to produce aprecipitation.

Accordingly, when an alkoxysilane compound having an amino group isused, except for carboxylic acid tin salts, carboxylate tin salts,carboxylic acid tin salt polymers, and carboxylic acid tin saltchelates, the same compound as those used in the case of an alkoxysilanecompound having an epoxy group can be used alone or as a mixture of twoor more compounds as a condensation catalyst.

The type of cocatalyst that can be used and combinations thereof; thetype of solvent; the concentrations of the alkoxysilane compound, thecondensation catalyst, and the cocatalyst; reaction conditions; and thereaction time are the same as those in the case of an alkoxysilanecompound having an epoxy group, and thus a description thereof isomitted.

In this embodiment, glass is used as the first base material.Alternatively, a metal such as aluminum, ceramics, or a synthetic resinsuch as an acrylic resin or polycarbonate can also be used.

When the base material has an active hydrogen group such as a hydroxylgroup or an amino group on the surface thereof, an alkoxysilane compoundcan be used as the film compound as in the case of glass. Specificexamples of such a base material include metals such as aluminum andceramics.

When a synthetic resin is used as the base material, by performing atreatment, for example, grafting a compound having an active hydrogengroup by a plasma treatment or the like, an alkoxysilane compound can beused as the film compound in some cases.

FIG. 1 shows a schematic view of the case where a monomolecular film ofa film compound having an epoxy group is formed on the entire surface ofthe first base material. Alternatively, the reaction mixture can beselectively applied onto only on the first joining surface using ascreen printing method, an ink jet printing method, or the like. In thiscase, the monomolecular film is not formed in an area of a channel of asolution. Accordingly, the biochemical chip according to the presentinvention can also be suitably used even in the case where a compoundthat reacts with a functional group or a coupling reactive groupcontained in the monomolecular film is used.

(The Above is Related to Step A)

In step B, a second film compound having an epoxy group is brought intocontact with a second joining surface 12 of a second base material 22made of glass to form a monomolecular film 14 of the second filmcompound having an epoxy group on the second joining surface 12 (seeFIG. 2). The film compound that can be used, reaction conditions, andthe like are the same as those in step A, and thus a detaileddescription thereof is omitted.

(The Above is Related to Step B)

In step C, first, 2-methylimidazole is brought into contact with themonomolecular film 13 of the first film compound to form a bond by acoupling reaction between an epoxy group and an amino group of2-methylimidazole, thereby forming a monomolecular film 15 of a2-methylimidazole derivative on the surface of the monomolecular film 13of the first film compound (see FIG. 3); and the first joining surface11 further having the monomolecular film 15 of the 2-methylimidazolederivative thereon is then brought into contact by pressure with thesecond joining surface 12 having the monomolecular film 14 of the secondfilm compound thereon to form a bond by a coupling reaction between anepoxy group and an imino group of 2-methylimidazole.

2-Methylimidazole has an amino group and an imino group, each of whichreacts with an epoxy group, at the 1-position and the 3-position,respectively, and forms bonds by a coupling reaction shown in Chem. 6below.

The monomolecular film 15 of the 2-methylimidazole derivative is formedby applying a reaction mixture prepared by mixing 2-methylimidazole anda solvent onto the monomolecular film 13 of the first film compoundformed on the first joining surface 11, and performing a reaction byheating. The application can be performed using any method such as adoctor blade method, a dip-coating method, a spin-coating method, aspray method, or a screen printing method.

In producing the reaction mixture, any solvent that can dissolve2-methylimidazole can be used. In view of the price, the volatility atroom temperature, the toxicity, and the like, a lower alcohol solventsuch as isopropyl alcohol or ethanol is preferable.

The amount of 2-methylimidazole added, the concentration of the mixtureapplied, the reaction temperature, and the reaction time areappropriately adjusted in accordance with, for example, the types ofbase material and film compound used.

After the reaction, washing is performed with a solvent to remove excess2-methylimidazole remaining on the surface as an unreacted product.Consequently, the monomolecular film 15 of the 2-methylimidazolederivative is further formed on the surface of the monomolecular film 13of the first film compound (see FIG. 3).

The first joining surface 11 further having the monomolecular film 15 ofthe 2-methylimidazole derivative thus obtained thereon and the secondjoining surface 12 having the monomolecular film 14 of the second filmcompound thereon are brought into contact with each other by pressureand heated. Consequently, the first joining surface 11 is adhered to thesecond joining surface 12 via a bond formed by a coupling reactionbetween the epoxy group on the monomolecular film 14 of the second filmcompound formed on the second joining surface 12 and an imino group ofthe 2-methylimidazole derivative covering the first joining surface 11,and thus the biochemical chip 10 is obtained (see FIG. 1).

The heating temperature is preferably in the range of 50° C. to 150° C.If the heating temperature is lower than 50° C., it takes a long time tocarry out the coupling reaction. If the heating temperature exceeds 150°C., a problem such as a decrease in the dimensional accuracy occurs.

Furthermore, when the adhesion is achieved while heating the first basematerial 21 and the second base material 22 at the same temperature,generation of thermal distortion after the adhesion can be suppressed toimprove the dimensional accuracy.

In this embodiment, 2-methylimidazole is used as a coupling agent.Alternatively, any imidazole derivative represented by Chem. 7 below canbe used.

Specific examples of the imidazole derivative represented by Chem. 7include compounds represented by (31) to (38) below.

2-methylimidazole (R₂=Me, R₄=R₅=H)  (31)

2-undecylimidazole (R₂=C₁₁H₂₃, R₄=R₅=H)  (32)

2-pentadecylimidazole (R₂=C₁₅H₃₁, R₄=R₅=H)  (33)

2-methyl-4-ethylimidazole (R₂=Me, R₄=Et, R₅=H)  (34)

2-phenylimidazole (R₂=Ph, R₄=R₅=H)  (35)

2-phenyl-4-ethylimidazole (R₂=Ph, R₄=Et, R₅=H)  (36)

2-phenyl-4-methyl-5-hydroxymethylimidazole (R₂=Ph, R₄=Me,R₅=CH₂OH)  (37)

2-phenyl-4,5-bis(hydroxymethyl)imidazole (R₂=Ph, R₄=R₅=CH₂OH)  (38)

Note that Me, Et, and Ph represent a methyl group, an ethyl group, and aphenyl group, respectively.

Alternatively, other than the imidazole derivative, a heterocycliccompound containing two or more nitrogen atoms, namely, melamine,isocyanuric acid, triazine, barbituric acid, parabanic acid, uracil,thymine, or the like can also be used. Furthermore, an imidazole-metalcomplex may also be used.

Alternatively, a compound such as an acid anhydride, e.g., phthalicanhydride or maleic anhydride; dicyandiamide; or a phenol derivative,e.g., novolac, each of which is used as a curing agent of an epoxyresin, can be used as the coupling agent. In such a case, an imidazolederivative may be used as a catalyst in order to accelerate the couplingreaction.

In this embodiment, a description is made of the case where a filmcompound having an epoxy group as a functional group is used. When afilm compound having an amino group or an imino group as a functionalgroup is used, a coupling agent having, as the coupling reactive groups,two or three or more epoxy groups, or two or three or more isocyanategroups is used.

When, for example, an epoxy group and an isocyanate group are used asthe coupling agent, coupling reactions shown in Chem. 8 and Chem. 9below occur, respectively.

Specific examples of the compound having isocyanate groups includep-phenylene diisocyanate, hexamethylene-1,6-diisocyanate,toluene-2,6-diisocyanate, and toluene-2,4-diisocyanate.

The amount of diisocyanate compound added is appropriately adjusted asin the case of 2-methylimidazole. In this case, examples of the solventthat can be used for producing the reaction mixture include aromaticorganic solvents such as xylene.

In addition, when a film compound having an amino group is used, acompound having two or three or more epoxy groups such as ethyleneglycol diglycidyl ether can also be used as the coupling agent.

In this embodiment, a coating film of 2-methylimidazole is formed inadvance, and adhesion is then achieved. Alternatively, a solution of2-methylimidazole may be applied on either one of or both of themonomolecular film of the first film compound and the monomolecular filmof the second film compound, and both the monomolecular films may thenbe brought into contact with each other by pressure to achieve adhesion.

(The Above is Related to Step C)

A biochemical chip and a method of producing the same have beendescribed here. An optical component can also be produced by the samemethod, and thus a detailed description thereof is omitted.

EXAMPLES

Examples performed in order to verify the advantages of the presentinvention will be described below, but the present invention is notlimited to these examples. In these examples, production of abiochemical chip and lens including a glass base material will bedescribed as typical examples.

Example 1 Production of Biochemical Chip (1) Formation of MonomolecularFilm of Film Compound Having Epoxy Group on Joining Surfaces ofBiochemical Chip Substrates

A pair of glass biochemical chip substrates (a channel having a channelwidth in the range of 10 to 100 μm and a depth of about 50 μm was formedon one of the substrates by photolithography and wet etching) wereprepared, sufficiently washed and then dried.

Subsequently, 0.99 parts by weight of3-glycidyloxypropyltrimethoxysilane (Chem. 10, manufactured by Shin-EtsuChemical Co., Ltd.) and 0.01 parts by weight of dibutyltinbisacetylacetonate (condensation catalyst) were weighed and thendissolved in 100 parts by weight of hexamethyldisiloxane to prepare areaction mixture.

The reaction mixture thus prepared was applied onto a joining surface ofeach of the substrates and allowed to react in air (relative humidity:45%) for about two hours. Subsequently, washing was performed withchloroform to remove excess alkoxysilane compound and dibutyltinbisacetylacetonate. A monomolecular film (having a thickness of about 1nanometer) of the film compound having an epoxy group was formed overthe entire joining surfaces.

(2) Formation of Monomolecular Film of 2-Methylimidazole Derivative

2-Methylimidazole dissolved in an alcohol was applied onto one of theepoxidized biochemical chip substrates on which the monomolecular filmwas formed in (1) and allowed to react under heating at 50° C. to 100°C. Washing was then performed with ethanol. Consequently, amonomolecular film of a 2-methylimidazole derivative was further formedon the surface of the monomolecular film of the film compound.

(3) Adhesion with Biochemical Chip Substrate

The biochemical chip substrate on which the monomolecular film of thefilm compound having an epoxy group was formed in (1) and thebiochemical chip substrate on which the monomolecular film of the2-methylimidazole derivative was formed in (2) were heated in advance at150° C. Both substrates were disposed so that the joining surfaces facedeach other, brought into contact with each other by pressure, and thenheated at 150° C. Consequently, a biochemical chip was obtained.

Example 2 Production of Cemented Lens

Adhesion of a cemented lens was achieved by the same method as inExample 1 using two lenses for a cemented lens. Regarding the resultingcemented lens, discoloration, distortion of the field of view,aberration, interference fringe formation, or the like was not observed.

REFERENCE NUMERALS

10: biochemical chip, 11: first joining surface, 12: second joiningsurface, 13: monomolecular film of a first film compound, 14:monomolecular film of a second film compound, 15: monomolecular film ofa 2-methylimidazole derivative, 21: first base material, 22: second basematerial, 23: hydroxyl group

1. A method of adhering a first joining surface of a first member to asecond joining surface of a second member, comprising: step A ofbringing a first film compound having a first functional group at an endof its molecule and a first surface bonding group at another end thereofinto contact with the first joining surface to form a bond between thefirst surface bonding group and a surface functional group of the firstjoining surface so as to form a coating film of the first film compoundon the first joining surface; step B of bringing a second film compoundhaving a second functional group at an end of its molecule and a secondsurface bonding group at another end thereof into contact with thesecond joining surface to form a bond between the second surface bondinggroup and a surface functional group of the second joining surface so asto form a coating film of the second film compound on the second joiningsurface; and step C of bringing the first joining surface having thecoating film of the first film compound thereon into contact by pressurewith the second joining surface having the coating film of the secondfilm compound thereon, while setting a coupling agent having at leastone first coupling functional group that forms a bond by a couplingreaction with the first functional group and at least one secondcoupling reactive group that forms a bond by a coupling reaction withthe second functional group to be in contact with the first functionalgroup and the second functional group to form bonds by couplingreactions: between the first functional group and the first couplingreactive group: and between the second functional group and the secondcoupling reactive group.
 2. The method of adhering according to claim 1,wherein, in step C, first, the coupling agent is brought into contactwith the coating film of the first film compound formed on the firstjoining surface to form a bond by a coupling reaction between the firstfunctional group and the first coupling reactive group so as to form acoating film of the coupling agent on the surface of the coating film ofthe first film compound, and the first joining surface further havingthe coating film of the coupling agent thereon is then brought intocontact by pressure with the second joining surface having the coatingfilm of the second film compound thereon to form a bond by a couplingreaction between the second functional group and the second couplingreactive group.
 3. The method of adhering according to claim 1, whereineach of the first functional group and the second functional group is afunctional group having an epoxy group, and the coupling agent is acompound having an imidazole group.
 4. The method of adhering accordingto claim 1, wherein each of the first surface bonding group and thesecond surface bonding group is an alkoxysilyl group.
 5. The method ofadhering according to claim 1, wherein, in step C, the first member andthe second member are heated at the same temperature.
 6. A biochemicalchip comprising: a first member and a second member, wherein, on a firstjoining surface of the first member, a coating film of a first filmcompound having a first functional group at an end of its molecule andbonded to the first joining surface at another end thereof is provided,on a second joining surface of the second member, a coating film of asecond film compound having a second functional group at an end of itsmolecule and bonded to the second joining surface at another end thereofis provided, the first functional group and the second functional groupare bonded to each other via bonds formed by coupling reactions: betweenthe first functional group and a coupling agent having at least onefirst coupling reactive group that forms a bond by a coupling reactionwith the first functional group and at least one second couplingreactive group that forms a bond by a coupling reaction with the secondfunctional group; and between the second functional group and thecoupling agent, and the first joining surface is adhered to the secondjoining surface via the formed bonds.
 7. The biochemical chip accordingto claim 6, wherein each of the first functional group and the secondfunctional group is a functional group having an epoxy group, and thecoupling agent is a compound having an imidazole group.
 8. Thebiochemical chip according to claim 6, wherein each of the coating filmof the first film compound and the coating film of the second filmcompound is a monomolecular film.
 9. An optical component comprising: afirst member and a second member, wherein, on a first joining surface ofthe first member, a coating film of a first film compound having a firstfunctional group at an end of its molecule and bonded to the firstjoining surface at another end thereof is provided, on a second joiningsurface of the second member, a coating film of a second film compoundhaving a second functional group at an end of its molecule and bonded tothe second joining surface at another end thereof is provided, the firstfunctional group and the second functional group are bonded to eachother via bonds formed by coupling reactions: between the firstfunctional group and a coupling agent having at least one first couplingreactive group that forms a bond by a coupling reaction with the firstfunctional group and at least one second coupling reactive group thatforms a bond by a coupling reaction with the second functional group;and between the second functional group and the coupling agent, and thefirst joining surface is adhered to the second joining surface via theformed bonds.
 10. The optical component according to claim 9, whereineach of the first functional group and the second functional group is afunctional group having an epoxy group, and the coupling agent is acompound having an imidazole group.
 11. The optical component accordingto claim 9, wherein each of the coating film of the first film compoundand the coating film of the second film compound is a monomolecularfilm.